AMD involves a loss of central vision as a result of a progressive degeneration of retinal and underlying tissues in people over the age of 50 years. Specific causes of significant loss in AMD are atrophy of the retina and the retinal pigment epithelium, and/or the growth of neovascularization with subsequent subretinal scarring. It is the main cause of irreversible blindness in the United States and Europe, and the prevalence appears to be increasing. Increasing rates are also being documented in Asia (Koh, A. H. C., et al., Ann. Acad. Med. 31:399-404, 2002). AMD accounts for about 50% of all cases of registered blindness in the west. Approximately 2 million Americans suffer vision loss from AMD, and over 10 million Americans show some early signs of AMD. The incidence of significant vision loss associated with AMD is about 2% for those at age 70, and 6% for those at age 80. (Hawkins, B. S., et al., Mol. Vis. 5:26, 1999; Vingerling, J. R., et al. Epidemiol. Rev. 17:347-360, 1995.) The total number of people with AMD is expected to triple by the year 2030. (Vinding, T., Acta Ophthalmologica 73 (Suppl): 1-32, 1995.)
Current methods of treatment have achieved only limited efficacy, and are ineffective if not started at a relatively early stage of the disease. Thus, there is a critical need in the art for methods of detecting AMD at a stage early enough to permit therapeutic treatment to prevent loss of vision, and to ultimately prevent development of the disease.